In recent years, conventional automotive suspensions have been modified to include inflatable and deflatable air springs. These suspensions, frequently referred to as air suspensions, are typically under electronic control and maintain a predetermined vehicle ride height relative to the wheels, regardless of fluctuations in the passenger/cargo weight. By maintaining ride height, fully loaded vehicles, or vehicles having uneven weight distributions, benefit from improved outward appearances, ride and improved handling.
For example, U.S. Pat. No. 5,083,275, issued to Kawagoe et al., discloses a height control system for an automotive suspension system with the vehicle driving condition dependent on variable target height. The vehicle height control system includes a suspension system which includes means for varying suspension force, a first sensor monitoring a vehicular height for producing height indicative for a sensor signal, a second sensor monitoring a vehicular driving condition to produce a vehicular driving condition indicative second sensor signal and a control means for receiving the first sensor signal. The control means checks the value of the sensor signal with respect to a predetermined target height range indicative values for deriving a control signal to operate the varying means to adjust the suspension for maintaining the vehicular height within the target height range. The control means defines the target height range in relation to a predetermined target height with a given acceptable height deviation from the target height, which acceptable deviation is variable depending upon the vehicle driving condition represented by the second sensor signal.
Existing air suspension systems either inhibit height corrections during acceleration (both positive and negative), or allow inaccurate corrections during accelerations, both positive and negative.